In the construction of stator assemblies for permanent magnet electric motors, magnets are retained within the stator assembly. For example, in a brush-type permanent magnet electric motor, magnets are retained on a stator housing or a separate flux ring within the stator housing. This generally requires gluing or adhering each individual magnet to the flux ring or stator housing.
Various types of adhesives have been used to adhere the magnets to the metallic surface. It is possible that a sudden shock to the electric motor will destroy the bond between the magnet and the flux ring or stator housing. This would result in movement of the magnet within the stator assembly. The magnet itself could even break. As a result, the electric motor ceases to properly function.
It is known in the art to provide an anchor in the flux ring or stator housing. Magnetic material is then injection molded on the flux ring or stator housing and is retained in position by the anchor. Such an anchor system is disclosed in U.S. Pat. No. 6,522,042 issued Feb. 18, 2003 entitled Anchoring System for Injection Molded Magnets on a Flux Ring or Motor Housing and in U.S. application Ser. No. 09/764,004 filed Jan. 17, 2001 entitled Anchoring System for Injection Molded Magnets on a Flux Ring or Motor Housing. However, a disadvantage of the anchoring systems described in the above-identified patent applications is that they require the use of injection molded magnetic material. This is typically the most expensive type of magnetic material per unit flux.